Pastebin has what are said to be details on plans for new Mass Effect 3 DLC found in the new extended cut of BioWare's action/RPG sequel. The spoilery post includes details on a plot involving a Reaper named Leviathan, and supporting the idea that more content for the game us coming is a new tweet by Mike Gamble noticed by Eurogamer which reads: "As I've said before, we do this for you! EC was our gift to the fans. Hope you enjoyed. Also...keep your ears open over the next little while." Thanks BioWare Social Network.

StingingVelvet wrote on Jun 27, 2012, 10:28:Finally started playing this, about 7 hours in right now. Will be very interested in seeing the original ending that pissed everyone off, so I haven't downloaded the DLC. People seem to think said ending ruins 3 amazing games worth of content and by itself is an example of Bioware's plummeting stock, so... will be interesting.

As far as I know (I do not remember seeing any extra "DLC" options for ME3 in Origin last night) it is not "DLC". It is slipstreamed into the main game as more of a patch. Meaning if you downloaded it off Origin you have the new endings.

Basically if you had ME3 installed before yesterday and opened Origin (required to play the game) your files are updated and you can't see the old endings sort of watching them on YouTube.